Also known as the Tau Canis Majoris cluster, because its bright central star Tau
Canis Majoris (4.39). The main star has an estimated mass between 40 to 50 solar masses. The star is a
luminous super giant with absolute magnitude of -7 or 50.000 solar luminosities. The cluster contains about 60 stars and it is 25 millions
old in age. A sweet visual target, even from urban skies, however because of its
small size long focal length are required. It was discovered by Giovanni
Battista Hodierna and published in 1654.